| We have characterized the photosynthetic response to ultraviolet radiation (UV) of natural phytoplankton assemblages in Antarctic (Southern Ocean) waters. Biological weighting functions (BWFs) and exposure response curves for inhibition of photosynthesis by UV were measured during spring-time ozone depletion (October-November). Two different models were developed to relate photosynthesis to UV exposure. A model that is a function of the duration of exposure (BWF H) applied to assemblages in the well-mixed open waters of the Weddell-Scotia Confluence (WSC, 60° S, 50° W), since responses were a function of cumulative exposure and recovery rates were slow. These assemblages had a variable but generally high sensitivity to UV. A steady-state model (BWF E)... |
